Probe card layout

ABSTRACT

Multi-touchdown, parallel test probe cards having probe elements arranged to provide greater than 99% efficiency during testing of a substrate having a plurality of die thereon, and methods of use.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention, in various embodiments, relates generally toprobe cards, and, more specifically, to arrangements of probe elementson a probe card.

2. Description of the Related Art

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

Generally, NAND memory chips are manufactured and tested in parallel.Conventionally, a grid of die is formed on a substrate usingsemiconductor manufacturing techniques. Once the die are formed, butbefore the substrate is diced to form chips, the die are tested forelectrical functionality and quality control. Testing certain types ofdie, such as NAND memory, can take a relatively long time, so a group ofdie is often tested concurrently, or “in parallel,” with a parallel testprobe card. Typically, the probe card includes a plurality of probeelements, which are each configured to test a single die.

Probe cards often have fewer probe elements than there are die on thesubstrate. Automated test equipment, which test the die via the probecard, have a finite capacity to test die in parallel. For example,signal bandwidth or processing power may limit the number of die thatthe automated test equipment can test at once. Thus, to test all of thedie on a substrate, the die are divided into multiple groups of die, andthe die within each group are tested in parallel. During testing, theprobe card is usually stepped across the substrate after each group ofdie is tested, until each of the groups, and thus all of the die on thesubstrate, have been tested. Each instance of testing a group of die inparallel on a single substrate is generally referred to as a“touchdown.” Thus, for example, half of the die on the substrate may betested in parallel during a first touchdown, and the other half of thedie on the substrate may be tested in parallel during a secondtouchdown.

Unfortunately, some probe cards do not always use the automated testequipment to its full capacity. Frequently, the probe elements on theprobe card are arranged such that some probe elements are not usedduring some touchdowns. For example, the probe elements may be arrangedso that every probe element aligns with a die when a first group of dieis tested, but some of these probe elements may be unused whensubsequent groups are tested on the same substrate, wasting automatedtest equipment capacity and reducing throughput.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the invention may become apparent upon reading thefollowing detailed description and upon reference to the drawings, inwhich:

FIG. 1 illustrates a substrate in accordance with an embodiment of thepresent invention;

FIG. 2 illustrates a die on the substrate of FIG. 1 in accordance withan embodiment of the present invention;

FIG. 3 illustrates a probe element in accordance with an embodiment ofthe present invention;

FIG. 4 illustrates a probe card in accordance with an embodiment of thepresent invention;

FIG. 5 illustrates a layout of probe elements on a probe card inaccordance with an embodiment of the present invention;

FIG. 6 illustrates a first plurality and second plurality of die on thesubstrate of FIG. 1 tested with the probe card of FIG. 5 in accordancewith an embodiment of the present invention;

FIGS. 7-9 illustrate other layouts of probe elements in accordance withembodiments of the present invention;

FIG. 10 illustrates a procedure for testing die on a substrate inaccordance with an embodiment of the present invention;

FIG. 11 illustrates a procedure for laying out probe elements on a probecard in accordance with an embodiment of the present invention; and

FIGS. 12-15 illustrate acts in the procedure of FIG. 11 in accordancewith an embodiment of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Various embodiments of the present invention will be described below. Inan effort to provide a concise description of these embodiments, not allfeatures of an actual implementation are described in the specification.It should be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

Some of the subsequently described embodiments may be configured to testdie on a substrate without wasting probe card capacity. As explainedbelow, certain embodiments may include probe elements arranged on aprobe card such that each probe element aligns with a die each time aplurality of die on the substrate are tested. In some embodiments, thesubsequently described probe cards may test multiple, non-overlappinggroups of die on a substrate without leaving a probe element on theprobe card idle during any of the touchdowns.

To highlight these features and others of the presently describedembodiments, the following discussion describes a substrate, a die, aprobe element, and a probe card. Then, several specific embodiments ofprobe element layouts are discussed, and an embodiment of a method fortesting die on a substrate is described. Finally, an embodiment of ageneralized procedure for generating probe element layouts is described.

Turning to the figures, FIG. 1 illustrates a substrate 100 according toan embodiment of the invention. The substrate 100 may include aplurality of die 102 arranged in rows 104 and columns 106. The rows 104and columns 106 may form a generally orthogonal grid or matrix of die102. The rows 104 and columns 106 may align with a flat segment or notch108 of the substrate 100 that indicates a particular orientation of acrystal structure of the substrate 100. The substrate 100 may includecrystalline semiconductive materials, such as silicon, gallium arsenide,indium phosphide, or other materials, for example. The substrate 100 maybe of a variety of sizes and support various numbers of die 102. Forinstance, the substrate 100 may be a 200 mm, 300 mm, or 400 mmsubstrate. Further, the number of die 102 may vary, depending, in part,on the size of the die 102 and the surface area of the substrate 100.

FIG. 2 depicts a die 102 on the substrate 100 in greater detail. The die102 may include one or more conductive pads 110. The illustrated pads110 are an electrical interface to integrated circuit devices on the die102. As explained further below, the die 102 may be tested byelectrically coupling to the die 102 via the pads 110. The die 102 mayinclude a variety of integrated circuit devices. For example, the die102 may be referred to or include NAND flash memory, NOR flash memory,dynamic random access memory, phase change memory, magneto-resistivememory, electrically erasable programmable read only memory, or othertypes of memory. In another example, the die 102 may include or bereferred to as a processor, a microcontroller, a graphics processor, adigital signal processor, an application specific integrated circuit, amixed signal chip, a controller, an image sensor, a complimentarymetal-oxide semiconductor image sensor, or other device.

A probe element according to an embodiment of the invention, such as theprobe element 112 depicted by FIG. 3, may interface with the die 102during testing. In the present embodiment, the probe element 112includes an array of pins 114, each having a contact 116. The contact116 of each pin 114 may correspond to a respective one of the pads 110on the die 102 (FIG. 2). When the probe element 112 is aligned with andpressed against the die 102, the contacts 116 may each make electricalcontact with one of the pads 110. In some embodiments, the pins 114resiliently move in response to the contact 116 being pressed against apad 110, as depicted by arrow 118.

In the present embodiment, the probe element 112 may be coupled to aprobe card 120, which may be used to interface between the probe element112 and automatic testing equipment. The probe card 120 may include aprinted circuit board (PCB) 122 having routing layers therein thatcouple to the pins 114. The PCB 122 may be disposed on a ceramic layer124. The ceramic layer 122 may have conductive contacts 126 thatinterface with the routing layers in the PCB 122. Another set ofcontacts 128 may couple the contacts 126 to automatic testing equipment.Thus, the probe card 128 may spatially transform the array of signalspassing through the closely spaced pads 110 on the die 102 to a largerarray of contacts 128 configured to interface with the automatic testingequipment. It should also be noted that, in some embodiments, capacitors130 may electrically isolate portions of the probe card 128 from straysignals originating in the automatic testing equipment.

FIG. 4 is a perspective view of a probe card 128 according to anembodiment of the invention. The probe card 128 is a parallel test probecard having a plurality of probe elements 112. That is, the probe card128 may be configured to simultaneously test a plurality of die 102 on asubstrate 100. When the probe card 128 is aligned with and pressedagainst the substrate 100, each of the probe elements 112 may align witha die 102 on the substrate, and the contacts 116 in each of the probeelements 112 may each align with one the pads 110 on one of the die 102.In other words, the probe card 128 electrically couples to a pluralityof die 102 during testing.

As explained above, each time the probe card 128 is electrically coupledto a plurality of die 102, the probe card 128 is said to have executed a“touchdown.” That is, the probe card 128 has touched down and tested agroup of die 102. In the present embodiment, the probe card 128 does notcouple to all of the die 102 in a single touchdown. Rather, a firstplurality of die 102 are tested in parallel, and then, a secondplurality of die 102 are tested in parallel, as explained further inreference to FIGS. 5 and 6.

FIG. 5 depicts a probe element layout 130 according to an embodiment ofthe invention. The layout 130 depicts the position of probe elements 112on a probe card 128. It is important to distinguish between the layout130, which depicts probe elements 112, and the substrate 100 of FIG. 1,which depicts the position of die 102. The probe elements 112 on thelayout 130 each align with one of the die 102 depicted on the substrate100 of FIG. 1. However, the number of probe elements 112 is less thanthe number of die 102, so there are blank or unoccupied areas 132 in thelayout 130. In some embodiments, the number of probe elements 112 may begreater than 50, 100, 200, 300, or 400.

FIG. 6 illustrates the relationship between the probe element layout 130and the die 102 on the substrate 100. In FIG. 6, the die 102 on thesubstrate 100 are divided into two groups: A and B, each correspondingto a touchdown of the probe card 128 on the substrate 100. That is, inthe present embodiment, group A is a plurality or set of die 102 thatare tested in parallel by the probe card 128, and group B is another,non-overlapping, plurality or set of die 102 that are tested in parallelby the probe card 128.

In operation, the probe card 128 is initially positioned over thesubstrate 100, with the substrate 100 facing upward and the side of theprobe card 128 with the probe elements 112 facing downward. The probeelements 112 may then be aligned with the set of die 102 in group A, andthe contacts 116 may be aligned with the pads 110 on each die 102. Toinitiate the first touchdown, the probe card 128 is lowered onto thesubstrate 100, and the pins 114 make contact with the pads 110 on thedie.

Once contact is made, automated test equipment may be used to test thedie 102 in group A in parallel. Various signals may be transmitted viathe probe card 128 to the die 102. For example, data may be written toand recalled from memory on the die 102. In other examples, imagesensors on the die 102 may transmit signals indicative of a light signaland/or various computations may be performed by logic units on the die102.

After the plurality of die 102 in group A have been tested, the probecard 128 may advance to the next group, e.g., group B. In the presentexample, the probe card 128 may elevate above the substrate 100 beforemoving to open the connections between the pins 114 in the probeelements 112 and the pads 110 on the die 102. Then, the probe card 128may shift to the right, as indicated by arrow 133, and align with thedie 102 in group B. Aligning with the die in group B may includealigning the contacts 116 in each probe element 112 with the pads 110 onthe die 102 in group B. Next, the probe card 128 may lower onto thesubstrate 110 to make contact, and the die 102 in group B may be testedin parallel. As explained further below, in some configurations, thisprocess may be repeated for additional groups of die 102, depending onthe ratio between the number of probe elements 112 and the number of die102 on the substrate 100.

Advantageously, the probe card 128 may achieve 100% efficiency in thepresent embodiment. For purposes of the present discussion, probe cardefficiency is calculated by dividing the number of testable die 102 onthe substrate 100 by the product of the number of touchdowns used totest all of the testable die 102 and the number of probe elements 112 onthe probe card 128. As indicated by FIG. 6, each probe element 112 onthe probe card 128 tests a die 102 in group A on the first touchdown,and each probe element 112 tests a die 102 in group B on the secondtouchdown. Further, group A and group B together include all of the die102 on the substrate 110, and group A and group B do not include any ofthe same die 102. Thus, when testing the die 102 on the substrate 100,the probe card 120 with layout 130 is 100% efficient (416 testabledie/(2 touchdowns * 208 probe elements)). That is, the probe card 128may be used to its full capacity during each touchdown. In someembodiments, the probe card 128 may test an entire substrate with fewertouchdowns than a conventional probe card because each touchdown maytest more die at once. Fewer touchdowns may, in turn, increase thethroughput of automated test equipment.

As explained further below, other embodiments may not achieve 100%efficiency but may still offer substantial improvements over othertechniques. For instance, some of the subsequently described embodimentsmay achieve efficiencies greater than 85%, 90%, 92%, 94%, 96%, 98%, or99%, while testing the substrate 100 with two touchdowns, threetouchdowns, four touchdowns, five touchdowns, or more. That is, certainembodiments may achieve high levels of efficiency while still satisfyingconstraints imposed by the automated testing equipment that prevent allof the die 102 from being tested in a single touchdown. In contrast,other layouts, such as a layout in which adjacent die on one half of thewafer are tested in parallel, may achieve maximum efficiencies of around83%, for example.

As a further advantage, the present embodiment may rapidly test many die102 by testing a large number of die 102 in parallel, rather than one ata time. As testing each individual die 102 may take a relatively longtime, testing multiple die 102 at once may increase the overallthroughput associated with the use of the probe card 128. For instance,the embodiment of FIG. 6 tests all of the die 102 on the substrate intwo touchdowns. Thus, the present embodiment may test all of the die 102in the time it takes to test two individual die 102. Other embodimentsmay facilitate testing all of the die 102 on the substrate 100 withfewer than four touchdowns, five touchdowns, six touchdowns, seventouchdowns, eight touchdowns, nine touchdowns, or ten touchdowns, forexample.

After the die 102 are tested, the substrate 100 may undergo furtherprocessing before the die 102 are singulated, packaged, and shipped orassembled with higher level packaging to form, for example, modules. Forexample, fuses on the die 102 may be blown to customize the die 102based on data gathered during testing. Die 102 that are not usable maybe marked based on the data gathered during testing. Finally, thesubstrate 100 may be diced and the die 102 packaged. The packaged die102 may be binned or categorized based on data gathered during testing,for instance the die 102 may be categorized based on data indicative ofoperating speed or data indicative of memory capacity.

FIG. 7-9 illustrates other embodiments of probe element layouts 134,136, and 138. In the embodiment of FIG. 7, the probe elements 112correspond to the first two consecutive die 102 on a row 104 on thesubstrate 100 (FIG. 1) and every other pair of die on the row 104. Thatis, within a row 104, adjacent probe elements 112 are separated byunoccupied areas 132 corresponding to two die 102. During operation, aprobe card 128 with layout 134 test a first group of die 102 in paralleland, then, shifts two die to the right (from the perspective of someonefacing the probe elements 112) to test a second group of die 102 inparallel. Thus, the embodiment of FIG. 7 may test all of the die 102 onthe substrate 100 in two touchdowns. Moreover, in some embodiments, thelayout 134 may achieve an efficiency of approximately 97% with thesubstrate 100 depicted by FIG. 1.

FIG. 8 illustrates another embodiment of a probe element layout 136. Inthe embodiment of FIG. 8, the probe elements correspond to the first die102 in a column 106 on the substrate 100 (FIG. 1) and every other die102 in the columns 106. During testing, a probe card 128 with the layout136 tests a first group of die and, then, shifts down one die 102 totest a different group of die 102 on the same substrate 100. The layout136 may be 100% efficient with the substrate 100 depicted by FIG. 1 andit may test all of the die 102 on the substrate 100 in two touchdowns.

FIG. 9 depicts another embodiment of a probe element layout 138 withfewer probe elements 112. In the present embodiment, the probe elements112 are positioned to correspond to the first die 102 in a row 104 onthe substrate 100 (FIG. 1) and every third die 102 in the row 104 to theright of the first die 102. That is, the probe elements 112 in thepresent embodiment may be separated by unoccupied space 132corresponding to a pair of die 102 on the substrate 100. In use, a probecard 128 with the layout 138 may test a substrate 100 with threetouchdowns. After the first touchdown, the probe card 128 may shift adistance corresponding to one die 102 to the right and a secondtouchdown may occur. Then, the probe card 128 may elevate and shiftanother time to the right over a distance corresponding to a single die102 for a third touchdown. Thus, the embodiment of FIG. 9 may becharacterized as a three-touchdown probe card layout 138. The layout 138may achieve 97% efficiency with the substrate 100 (FIG. 1).

An embodiment of a procedure for testing die 102 on the substrate 100 isdepicted by FIG. 10. In a first act, a first half of the die 102 on thesubstrate 100 may be simultaneously tested using each and every probeelement 112 on the probe card 128, as depicted by block 142. In otherwords, in the present embodiment, no probe elements 112 are idle whiletesting the first half of the die 102. Then, a second half of the die102 on the substrate 100 are simultaneously tested using each and everyprobe element 112 on the probe card 128, as depicted by block 144. Thatis, while testing both the first half of the die 102 and the second halfof the die 102, no probe element 112 on the probe card 128 is unused.

FIGS. 11-15 depict embodiment of a procedure for generating probe cardlayouts 146. Specifically, FIG. 11 describes acts that may be includedin the procedure 146, and FIGS. 12-15 indicate how probe elements may bepositioned in accordance with certain acts described by FIG. 11. Itshould be noted that the probe card layout developed in FIGS. 12-15 isnot necessarily optimal and was selected for its explanatory valuerather than its efficiency. As explained below, the terminology used todescribe the layouts developed in FIGS. 12-15 may be used to conciselydescribe a variety of embodiments that are highly-parallel and highlyefficient.

Turning to FIG. 11, the embodiment of the procedure 146 begins withselecting a horizontal direction in reference to a substrate 100, asdepicted block 148. Here, the term “horizontal” refers to a directionthat is parallel to the surface of the substrate 100 on which die 102are formed. Thus, for example, the x or y direction in FIG. 1,corresponding to the directions in which the rows 104 and columns 106extend, may be selected.

FIG. 12 depicts a reference substrate 100 that identifies die 154 towhich probe elements 112 are to be aligned during the proceduredescribed by FIG. 11, as described further below. In FIG. 12, theselection of a direction is indicated by arrow 150, which corresponds tothe direction in which the rows 104 extend (the x-direction).

Next, a first subset of probe elements 112 may be placed on a probe card128 at locations that align with a first subset of die 154 consisting ofeach peripheral die 154 disposed furthest in a direction opposite theselected direction, as depicted by block 152 of FIG. 11. The shaded die154 illustrate the position of probe elements 112 that may be positionedin accordance with this act. On circular substrates 100, the subset ofprobe elements 112 positioned in this step may generally form an arc156.

Returning to FIG. 11, next in the embodied procedure 146, a secondsubset of probe elements 112 may be positioned on the probe card 128 atlocations that align with a second subset of die 154 consisting of the ndie adjacent the first subset of die 154 in the selected direction 150,as depicted by block 158. In the embodiment illustrated by FIG. 13, n=1,and the direction 150 is left-to-right (i.e., in the x-direction). Thus,the first die 154 to the right of the previously aligned to die 154 (inFIG. 12) define the position of the probe elements 112 positioned inthis act. It should be noted that this step, like many of the othersteps and features discussed herein, is optional.

Next, another arc 160 is formed by placing a third subset of probeelements 112 on the probe card 128 at locations that align with a thirdsubset of die 154 consisting of the die m die away from the secondsubset in the direction 150, as depicted by block 160 in FIG. 11. Thatis, unoccupied space corresponding to m die is defined on the probe card128 between the previously placed probe elements 112 and the probeelements 112 placed in the present act. In the embodiment depicted byFIG. 14, m=3, and the next subset of probe elements 112 are placed toalign with a subset of die 154 three die to the right of the die 154 towhich the previously placed subset of probe elements 112 aligned. Again,the probe elements 112 in this subset may generally form an arc 160located a distance corresponding to m+n+1 die away from the previous arc156 in the direction 150.

In some embodiments, a fourth subset of probe elements 112 may be placedon the probe card 128 at locations that align with a fourth subset ofdie 154 including the n die adjacent the third subset of die 154 in thedirection 150, as depicted by block 162 in FIG. 11. It should be notedthat, as with the other acts, this act is optional.

Next, the acts depicted by blocks 160 and 162 of FIG. 11 may be repeatedfor each full or partial subset of n+1 die disposed m die over in thedirection 150 from the die 154 to which probe elements 112 werepreviously aligned, as depicted by block 164. Four more repetitions areexemplified by FIG. 15, in which four additional arcs 166 of probeelements 112 are placed to align with die 154.

As illustrated by the pattern of die 154 to which probe elements 112 arealigned in FIG. 15, the probe elements 112 may generally form a seriesof arcs 156, 160, and 166. Each arc 156, 160, and 166 may represent asubset of die 154 plus n adjacent die 154 in the direction 150 on thesubstrate 100 to which a probe element 112 is aligned. The arcs 156,160, and 166 may have a center that is shifted in the direction 150 by adistance corresponding to n+m+1 away from other arcs 156, 160, or 166.In the present embodiment, m and n are integer multiples of the pitch ofthe die 102 in the selected direction 150.

A taxonomy of the previously discussed embodiments may be developed withreference to the parameters described in FIGS. 11-15. For example, FIGS.5, 7, 9, and 15 depict probe card 128 layouts in which the selecteddirection 150 is to the right (the x-direction) relative to the notch108 on the substrate 100. In contrast, FIG. 8 depicts a probe card 128where the selected direction 150 is down (or in the negativey-direction) relative to the notch 108 on the substrate 100.

The parameters m and n from FIG. 15 may also be used to characterizeprobe card 128 layouts. FIGS. 5, 8, and 9 depict probe card 128 layoutswith n values equal to zero, and FIGS. 7 and 15 depict probe card 128layouts with n values equal to 1. Similarly, FIGS. 5 and 8 illustrateprobe card 128 layouts with m values of 1, FIGS. 7 and 9 illustrateprobe cards 128 with m values of 2, and FIG. 15 illustrates a probe cardlayout with an m value of 3.

Other embodiments may include probe cards 128 with layouts characterizedby different selected directions 150, m values, n values, orcombinations thereof. For instance, the selected direction 150 may beleft, right, up, down, or at some other angle. Similarly, in certainembodiments, the m value and/or n value may be 1, 2, 3, 4, 5, 6, 7, 8,9, 10, or other values.

The number of touchdowns a probe card 128 performs to test all of thedie 102 on the substrate 100 may correlate to the m and n values. Forinstance, in some embodiments, the m value may equal n+1 to produce atwo-touchdown probe card 128, e.g., in the embodiment of FIG. 5. Inanother example, the m value may be twice as large as n+1 to produce athree-touchdown probe card 128, e.g., in the embodiment of FIG. 9. Moregenerally, in certain embodiments, the probe card 128 may becharacterized as an x-touchdown probe card 128 where x is equal to1+m/(n+1).

To summarize, certain probe cards 128 developed in accordance with theacts described by FIGS. 11-15 facilitate use of automated test equipmentto its full capacity. As explained above, various factors may limit thenumber of die that automated test equipment may test in parallel. Thesefactors may determine the number of probe elements 112 on a probe card128, which may be less than the number of die 102 on the substrate 100,and which may lead to multiple touchdowns to test all of the die 102 onthe substrate 100. Unused probe elements 112 during any of thetouchdowns may be indicative of unused automated test equipmentcapacity. Certain embodiments may minimize unused capacity by minimizingthe number of unused probe elements and testing many die simultaneously.That is, certain embodiments may be both highly parallel (i.e., they mayuse a large portion of the capacity of the automated test equipment inan individual touchdown) and highly efficient (i.e., they may use alarge portion of the capacity of the automated test equipment in everytouchdown). Thus, the previously discussed embodiments may tend toreduce the amount of automated test equipment capacity that is unusedduring the testing of a substrate 100.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

1. A method, comprising: simultaneously testing a first plurality of dieon a substrate using a probe card having a plurality of probe elements,wherein each and every one of the plurality of probe element is alwaysto test a respective one of the first plurality of die on the substrate;and simultaneously testing a second plurality of die on the substrateafter testing the first plurality of die, wherein each and every one ofthe plurality of probe elements is always employed to test a respectiveone of the second plurality of die on the substrate.
 2. The method ofclaim 1, wherein the first plurality of die does not share any die withthe second plurality of die.
 3. The method of claim 1, comprisingshifting the probe card a distance generally corresponding to a singledie after testing the first plurality of die and before testing thesecond plurality of die.
 4. The method of claim 1, comprisingsimultaneously testing a third plurality of die on the substrate aftertesting the second plurality of die.
 5. The method of claim 1,comprising manufacturing a plurality of integrated circuit die on asubstrate.
 6. The method of claim 5, wherein the integrated circuit diecomprise NAND flash memory.
 7. The method of claim 5, comprisingsegmenting the integrated circuit die on the substrate and packaging theintegrated circuit die.